1. Field of the Invention
The present invention relates to optical fiber connectors and, more particularly, to chips for use in connecting optical fiber ribbon cables.
2. Brief Description of Prior Developments
As fiber optics emerged in the mid 1970's, engineers improved data transmission rates to 45 megabits per second over 24 fibers using single fiber connectors. Twenty years later, a 32 fiber parallel array system can transmit 16 Gb/s for computer technology requiring faster transmission rates exceeding the coaxial capacities and lengths. Several array technologies and consortiums have evolved that incorporate the parallel fiber array technology. The list includes Optoelectronic Technology Consortium (OETC) composed of AT&T, IBM, Honeywell and Martin Marietta.
The OETC group has developed a 32 channel optical link by introducing new packaging techniques for the devices and optical fibers. The transmitter and receiver modules were designed to eliminate pigtails by connecting directly to the fiber optic cable assemblies. The fiber density was increased in the devices, connectors and cables by maintaining a tighter pitch between fibers. New test procedures were developed for the 18 fiber test units to address the new 32 fiber cable. The higher density MACII.RTM. in the standard connector shell maintains compatibility through existing connector designs.
Conventional MACII.RTM. configurations include the 18 and 32 fiber chips. The 18 fiber chips place the fibers on 250 micron centers since the fiber's construction limits the higher densities in a single dimension with the MACII.RTM. hardware. The ribbonized fibers (62.5/125/250) core/cladding/buffer dimensions in microns) are placed side by side in a single row. When the 18 fibers are ribbonized in a single layer, 18.times.1, buffer to buffer, the fiber's centers require 250 micron spacing since the buffers control the linear layout. During the assembly, the buffer material is removed 9.5 millimeters from the fiber end to expose the 125 micron cladding. Though the 18 Fiber MACII.RTM. chips house the 125 micron diameters, the 250 buffers space the fibers 250 microns apart. In OETC, MACII.RTM. standard parts are used with a 32 fiber chip design. In the 32 fiber chip, a 62.5/125/135 fiber placed on 140 micron centers increased the density. It will be understood that the preferred groove dimensions disclosed in connection with FIGS. 36-38a below will be for the fiber shown in FIG. 35a and that these dimensions will be adjusted for the larger fiber shown in FIG. 38b.